1. Field of the Invention
The present invention relates to power tools, and more particularly to electrically powered cutting tools having independently powered dust control.
2. Description of the Prior Art
Table saws, miter saws, bandsaws, circular saws, drills, sanders, and like tools are used to cut materials such as virgin lumber, composite lumber, plasterboard, and the like. Cutting such materials immediately generates large quantities of dust. This dust may present health hazards to people, may obscure the work, and in some instances may present hazards such as fire or explosion hazards.
Obscuring of the work aggravates a condition which plagues cutting tools, namely, that the actual point of contact of the cutting tool with a workpiece is obscured by the conditions of work under the best of circumstances. This situation has been addressed by provision of a light for illuminating the workpiece at the point of contact with the cutting tool. However, effective lighting of this aspect of cutting work remains delicate. The lamp must bear advantageously on the apparatus, not being shielded or obstructed by a blade or the like for example. Also, the light must be sufficiently robust to withstand the conditions of work.
One condition of work is that of temperature. While light sources such as light emitting diodes and compact fluorescent lamps are desirable in that they are highly efficient, they are also subject to the problem of dissipation of heat. These types of light sources must be well ventilated in order to avoid damage by heat. The dusty environment of cutting work further aggravates this problem as dust tends to permeate everywhere and to interfere with effective ventilation.
Dust collection and suppression apparatuses have been proposed. A vacuum source or pressure source may be introduced to work in cooperation with a powered cutting tool to collect, dispose, or suppress dust.
However, many powered cutting tools are provided that do not incorporate or cooperate with dust collectors or suppressors. Vacuum and other pressure based devices may be obtained and operated in tandem with electrical cutting tools. However, if an independent electrically operated vacuum or blowing device is utilized in tandem with an electrically powered cutting tool, there can arise problems in managing electrical supply and control functions.
This is particularly true where the cutting tool is to be utilized in residential settings. Modern residences are typically provided with general purpose electrical circuits to support transient loads such as power tools. However, some power tools operate at power levels approaching the limits of the ampacity which can be sustainably supplied by general purpose electrical circuits. It may be necessary therefore to provide power to a cutting tool from one circuit, and to provide power to an auxiliary load, such as a vacuum or blowing device in order to collect, control, or suppress dust generated by the cutting tool.
Connecting two independent motors to power sources based on two circuits further presents an inconvenience, namely, redundant switching and controlling of the two motors. It becomes necessary to operate two switches each time the two motors are to be switched on or off. This can become quite annoying if the vacuum or pressure device has a switch which is located away from that of the cutting tool. Therefore, there exists a need to provide for convenient switching of separate motors supplied from different electrical circuits. More particularly, it would be desirable to effect simultaneous switching of two motors from the switch of the cutting tool.